Comparison of 20-Year Obesity-Associated Cancer Mortality Trends With Heart Disease Mortality Trends in the US

IMPORTANCE: Heart disease and cancer are the 2 major diseases associated with mortality risk in the United States. Four decades of improvements in heart disease mortality slowed after 2011; this slowing has been associated with the obesity epidemic. The same pattern has not been observed for total cancer mortality. However, trends in total cancer mortality may obscure patterns specific to obesity-associated cancers. OBJECTIVE: To investigate whether trends in obesity-associated cancer mortality mirror the slowed mortality improvements observed for heart disease associated with the obesity epidemic. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study compared US mortality trends for International Statistical Classification of Diseases and Related Health Problems, Tenth Revision–defined cancer (total cancer, obesity-associated cancer, and cancer not associated with obesity) and heart disease deaths from January 1, 1999, to December 31, 2018. Data were included on decedents with complete information on the underlying cause of death, age, sex, race, and ethnicity. EXPOSURES: Changes in age-adjusted cause-specific mortality rates between 1999-2011 and 2011-2018 were compared. MAIN OUTCOMES AND MEASURES: Annual relative rates of change in age-adjusted mortality rates (AAMRs) in the overall population and stratified by sex, race, and ethnicity were estimated using Poisson regression. Differences in AAMR annual relative rates of change before and after 2011 were evaluated using Wald tests. RESULTS: A total of 50 163 483 decedents met the inclusion criteria (50.1% female decedents, 79.9% non-Hispanic White decedents, and 11.7% non-Hispanic Black decedents; mean [SD] age, 72.8 [18.5] years). In contrast with heart disease mortality, for which improvements slowed between 1999-2011 and 2011-2018, decreases in total cancer AAMR relative change accelerated between 1999-2011 (−1.48 [95% CI, −1.43 to −1.52]) and 2011-2018 (−1.77 [95% CI, −1.67 to −1.86]) (P < .001). For obesity-associated cancer mortality, which accounted for approximately 33% of total cancer deaths annually, decreases in annual AAMR relative change decelerated from −1.19 (95% CI, −1.13 to −1.26) in 1999-2011 to −0.83 (95% CI, −0.70 to −0.96) in 2011-2018 (P < .001). The largest decelerations in obesity-associated cancer mortality were observed for female decedents (–1.45 [95% CI, –1.36 to –1.53] in 1999-2011 and –0.91 [95% CI, –0.75 to –1.07] in 2011-2018; P < .001) and non-Hispanic White individuals (–1.16 [95% CI, –1.09 to –1.22] in 1999-2011 and –0.68 [95% CI, –0.55 to –0.81] in 2011-2018; P < .001). CONCLUSIONS AND RELEVANCE: Slowing improvements in obesity-associated cancer mortality were obscured when considering total cancer mortality. These findings potentially signal a changing profile of cancer-associated mortality that may parallel trends previously observed for heart disease as the consequences of the obesity epidemic are understood.